WASHINGTON — Homeland Security Director Michael Chertoff on Sunday defended the government’s security review of an Arab company given permission to take over operations at six major U.S. ports.

“We have a very disciplined process, it’s a classified process, for reviewing any acquisition by a foreign company of assets that we consider relevant to national security,” Chertoff told Tim Russert on “Meet the Press.”

London-based Peninsular and Oriental Steam Navigation Co., was bought last week by Dubai Ports World, a state-owned business from the United Arab Emirates. Peninsular and Oriental runs major commercial operations in New York, New Jersey, Baltimore, New Orleans, Miami and Philadelphia.

“We don’t take a risk. What we do is we require a very careful review—we have the FBI involved, we have the Department of Defense involved—of what the challenges are. We have, in fact, dealt with this port before because we deal with it overseas as part of our comprehensive global security network,” Chertoff said.

“We’ve built in, and we will build in safeguards to make sure that these kinds of things don’t happen. And, you know, this is part of the balancing of security, which is our paramount concern, with the need to still maintain a real robust global trading environment.”

U.S. lawmakers from both parties are questioning the sale, approved by the Bush administration, as a possible risk to national security.

“It’s unbelievably tone deaf politically at this point in our history,” Sen. Lindsay Graham, R-S.C. said on “Fox News Sunday.”

“Most Americans are scratching their heads, wondering why this company from this region now,” Graham said.

Sen. Barbara Boxer, a California Democrat, said she would support legislation to block foreign companies from buying port facilities.

“I’m going to support legislation to say ‘No more, no way.’ We have to have American companies running our own ports ... Our infrastructure is at risk,” she said on CBS’s “Face the Nation.”

Added Sen. Evan Bayh, D-Ind.: “I think we’ve got to look into this company. We’ve got to ensure ... the American people that their national security interests are going to be protected.”

At least one Senate oversight hearing is planned for later this month.

“Congress is welcome to look at this and can get classified briefings,” Chertoff told CNN’s “Late Edition.”

“We have to balance the paramount urgency of security against the fact that we still want to have a robust global trading system,” he added.

Sen. Robert Menendez, who is working on legislation to prohibit companies owned or controlled by foreign governments from running port operation in the U.S., said Chertoff’s comments showed him that the administration “just does not get it.”

In a statement, the New Jersey Democrat said, “No matter what steps the administration claims it has secretly taken, it is an unacceptable risk to turn control of our ports over to a foreign government, particularly one with a troubling history. We cannot depend on promises a foreign government has given the administration in secret to secure our ports.”

Chertoff said Dubai Ports World should not be excluded automatically from such a deal because it is based in the UAE.

Critics have cited the UAE’s history as an operational and financial base for the hijackers who carried out the attacks of Sept. 11, 2001.

In addition, they contend the UAE was an important transfer point for shipments of smuggled nuclear components sent to Iran, North Korea and Libya by a Pakistani scientist.

DP World has said it intends to “maintain and, where appropriate, enhance current security arrangements.” The UAE’s foreign minister has described his country as an important U.S. ally in fighting terrorism.